Avalanche Advisory for Thursday February 07,2013

Expires at Midnight Thursday 2-07-2013

Tuckerman Ravine has LOW and MODERATE avalanche danger. The Lip and Center Bowl have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Evaluate snow and terrain carefully to identify features of concern. All other forecast areas have Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features. These pockets do exist.

Huntington Ravine has LOW avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features.

High winds, peaking at 93mph (150kph) yesterday, moved the remaining snow from alpine zones and 1.5” (3.75cm) of new snow into several strong lee areas in Tuckerman.  The most new snow was delivered into the Lip down to the “open book” near Lunch Rocks. This entire climber’s right side of the center Bowl picked up the most snow.  As you move left towards the center, and right to the Sluice, more, old gray surface is showing.  The Sluice and the Chute are posted at Low but isolated pockets of new slab do exist, these two forecast areas are the Low rated locales to pay the most attention to.  In the Sluice, most new snow exists as a climber heads left away from the big pitch of ice in the center.  New snow is also found in small fields as you travel from the Sluice towards the Lip, these pockets are small but can be a stability issue.  The Chute also has isolated new slab on the climber’s right after the constriction of the rock buttress.  This is a classic minor terrain rollover convexity that we have seen avalanche in the past. This petite, yet consequential, locale can be avoided by staying more towards the center or climber’s left in the gully proper.

Well enough of the nano-forecasting now let’s look at the big picture!  The breath of the white dragon is upon us as the mountains brace for the looming Nor’easter.  The NWS has issued a Winter Storm Watch beginning Friday afternoon until Saturday. Areas south of the Whites are expected to see upwards of 2 feet while we are expected to see about half that, perhaps a bit more.  Precipitation should start tomorrow with winds from the S and begin a slow, but steady, march through the SE,E, and eventually to the N by Saturday morning.  This event should be a big gainer for the Ravines due to initial lower wind speeds. As winds wrap counterclockwise around the compass rose moderate speeds in the 40’s mph are expected until they become more northerly.  This will cross load a number of S and N facing slopes with new slab.  Once out of the north, velocities will pick up on Saturday loading areas such as North, Damnation and Yale in Huntington, as well as The Lobster claw, Right gully, the Sluice, and the Lip in Tuckerman with copious amounts of new snow. Into the weekend as a NW flow becomes established even more new slab will load in the depositions of SE and E facing slopes.  More on all this tomorrow as models all come into agreement and the track becomes more clear.  Be ready for an increasing avalanche danger with some of the red “High” slats coming out if the system stays on par with expectations.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin. Posted 8:35a.m. 02-07-2013. A new advisory will be issued tomorrow.

Christopher Joosen, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2013-02-07 Print Version